Energy Changes questions

By Interwoven Maths

Energy Changes question collection

Review Energy Changes questions for Chemistry, with correct answers shown and coverage across exothermic and endothermic reactions; reaction profile diagrams; activation energy.

Back to Energy Changes practice Back to Chemistry

Question 1

An exothermic reaction transfers energy?
  1. To the surroundings
  2. From the surroundings
  3. To catalysts
  4. To reactants

Question 2

An endothermic reaction transfers energy?
  1. From the surroundings
  2. To the surroundings
  3. As light to the room
  4. Into products with no surroundings effect

Question 3

Where are products shown on an exothermic reaction profile?
  1. Below the reactants
  2. Above the reactants
  3. Level with the reactants
  4. At the activation-energy peak

Question 4

What is activation energy?
  1. Minimum energy needed for a successful reaction
  2. The total energy released by products
  3. The energy stored only in catalysts
  4. The energy needed to cool reactants

Question 5

How does a catalyst speed up a reaction?
  1. By providing an alternative pathway with lower activation energy
  2. By increasing the overall energy change, ΔH
  3. By being used up to release heat
  4. By increasing reactant mass

Question 6

Breaking chemical bonds requires?
  1. An input of energy
  2. Release of energy
  3. No energy change
  4. A change in pH

Question 7

What happens to energy when chemical bonds form?
  1. It is released
  2. It is absorbed
  3. It is unchanged
  4. It becomes activation energy

Question 8

Bond making releases more energy than bond breaking. Which type of reaction?
  1. Exothermic
  2. Endothermic
  3. Thermal decomposition
  4. Reversible reaction

Question 9

Which equation is used in simple calorimetry?
  1. q = mcΔT
  2. q = mΔT / c
  3. q = cΔT / m
  4. q = mc / ΔT

Question 10

\(100\,\mathrm{g}\) of water is heated by \(5\,\mathrm{^\circ C}\). Use \(c = 4.2\,\mathrm{J\,g^{-1}\,^\circ C^{-1}}\). What is \(q\)?
  1. \(2100\,\mathrm{J}\)
  2. \(840\,\mathrm{J}\)
  3. \(21000\,\mathrm{J}\)
  4. \(500\,\mathrm{J}\)

Question 11

Which reaction type is usually exothermic?
  1. Neutralisation of an acid and an alkali
  2. Thermal decomposition
  3. Photosynthesis
  4. Electrolysis of molten salts

Question 12

Which process is usually endothermic?
  1. Thermal decomposition of calcium carbonate
  2. Combustion of methane
  3. Respiration
  4. Condensation of steam

Question 13

A chemical cell produces electricity from what type of reaction?
  1. A redox reaction
  2. A thermal decomposition reaction
  3. A neutralisation reaction
  4. A precipitation reaction

Question 14

When does a cell made from two metals give a higher voltage?
  1. Further apart in reactivity
  2. Next to each other in reactivity
  3. Both equally unreactive
  4. Identical metals in identical conditions

Question 15

In a hydrogen fuel cell, hydrogen reacts with oxygen to form?
  1. Water
  2. Hydrogen peroxide
  3. Carbon dioxide
  4. Methane

Question 16

What is one advantage of hydrogen fuel cells at point of use?
  1. It produces water rather than carbon dioxide
  2. It produces carbon dioxide rather than water
  3. It releases hydrogen as the main product
  4. It stores charge without a chemical reaction

Question 17

On reaction profiles, what sign is ΔH for exothermic reactions?
  1. Negative
  2. Positive
  3. Zero
  4. The same sign as activation energy

Question 18

Breaking bonds needs \(250\,\mathrm{kJ\,mol^{-1}}\); forming bonds releases \(400\,\mathrm{kJ\,mol^{-1}}\). What is \(\Delta H\)?
  1. \(-150\,\mathrm{kJ\,mol^{-1}}\)
  2. \(+150\,\mathrm{kJ\,mol^{-1}}\)
  3. \(-650\,\mathrm{kJ\,mol^{-1}}\)
  4. \(+650\,\mathrm{kJ\,mol^{-1}}\)

Question 19

Why is breaking bonds endothermic?
  1. Energy is required to overcome attractions
  2. Energy is released when attractions are overcome
  3. Atoms are destroyed
  4. Electrons are made

Question 20

What is a reaction profile?
  1. Energy plotted against the progress of the reaction
  2. Rate plotted against time
  3. Mass plotted against volume
  4. Concentration plotted against temperature

Question 21

Where are products shown on an endothermic reaction profile?
  1. Above the reactants
  2. Below the reactants
  3. Level with the reactants
  4. At zero energy

Question 22

What does a calorimeter measure in school experiments?
  1. Temperature change caused by a reaction
  2. Number of moles directly
  3. Mass of electrons
  4. pH

Question 23

A \(1\,\mathrm{kg}\) sample has \(c=500\,\mathrm{J\,kg^{-1}\,{}^\circ C^{-1}}\). What energy raises it by \(2\,{}^\circ\mathrm{C}\)?
  1. \(1000\,\mathrm{J}\)
  2. \(250\,\mathrm{J}\)
  3. \(500\,\mathrm{J}\)
  4. \(1002\,\mathrm{J}\)

Question 24

What does a larger potential difference in a cell indicate?
  1. A greater difference in energy between the reactions
  2. A lower energy difference between reactions
  3. A larger number of electrons in each atom
  4. A lower concentration of reactants

Question 25

What is a disadvantage of hydrogen fuel cells?
  1. Hydrogen production and storage can be difficult
  2. Hydrogen has a high energy per unit mass
  3. Water is produced at point of use
  4. A fuel cell can be refuelled quickly

About this topic

Review Energy Changes questions for Chemistry, with correct answers shown and coverage across exothermic and endothermic reactions; reaction profile diagrams; activation energy.

This topic covers

Example question types